GetFullPath in Mapped

Código para buscar o endereço completo de uma pasta mapeada na rede.

Ex: Z:/

 #region GetFullPath in Mapped    
   [DllImport("mpr.dll", CharSet = CharSet.Unicode, SetLastError = true)]  
   private static extern int WNetGetConnection(  
     [MarshalAs(UnmanagedType.LPTStr)] string localName,  
     [MarshalAs(UnmanagedType.LPTStr)] StringBuilder remoteName,  
     ref int length);  
   private static string GetUNCPath(string originalPath)  
   {  
    StringBuilder sb = new StringBuilder(512);  
    int size = sb.Capacity;  
    // look for the {LETTER}: combination ...  
    if (originalPath.Length > 2 && originalPath[1] == ':')  
    {  
     // don't use char.IsLetter here - as that can be misleading  
     // the only valid drive letters are a-z && A-Z.  
     char c = originalPath[0];  
     if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))  
     {  
      int error = WNetGetConnection(originalPath.Substring(0, 2), sb, ref size);  
      if (error == 0)  
      {  
       DirectoryInfo dir = new DirectoryInfo(originalPath);  
       string path = Path.GetFullPath(originalPath).Substring(Path.GetPathRoot(originalPath).Length);  
       return Path.Combine(sb.ToString().TrimEnd(), path);  
      }  
     }  
    }  
    return originalPath;  
   }  
   #endregion